The objective of the proposed research is to evaluate the staff and family proxy responses about the quality of life (QoL) of nursing home residents unable to self-report. Specifically, the aims are: 1) to describe the extent and nature of agreement across family and staff proxies reporting on the QoL of nursing home residents unable to respond to an interview as well as across different proxies and residents able to respond; 2) to determine how characteristics of the study subjects (nursing home residents), characteristics of the proxies (family, staff), and characteristics of the questions asked affect the concordance of the data from the different proxies, including: a) whether agreement is related to functional and/or cognitive status of residents; b) what characteristics of the proxies (family and staff) affect agreement; c) what characteristics of the questions asked (i.e., how information is obtained by the proxy or how well the proxy must know the subject) relate to the level of agreement among proxies; and d) if variables or combinations of characteristics improve agreement across proxies; and 3) to explore empirical means of determining when and the extent to which agreement across proxies is an indication of validity. [unreadable] [unreadable] The study uses data from an effort to design measures of QoL of nursing home residents that collected information about residents from several different sources. Models of the processes used in answering questions developed by cognitive psychology serve as the basis for the selection of the characteristics of the nursing home residents, the proxies, and the questions hypothesized to affect proxy agreement. Analyses include measures of agreement, a graphically-based approach to quantifying systematic differences in responses, and simulations to determine what combinations of characteristics increase probability of agreement. [unreadable] [unreadable] Proxies are important sources of information in health studies, particularly in populations for whom QoL is a desired outcome. Moreover, promoting QoL should be a priority in long-term care, particularly nursing homes. A better understanding of proxies can enhance the ability to measure, monitor and improve QoL. [unreadable] [unreadable]